1. Field of the Disclosure
The present disclosure relates to a liquid crystal display device, and more particularly, to a liquid crystal display device which is configured to create an aesthetic effect while on low power by performing a single color driving operation in standby mode.
2. Description of the Conventional Art
With the development of electronic information equipment, such as mobile phones, portable devices such as laptop computers, and HDTVs, which deliver high-resolution, high-quality images, the demand for flat panel display devices applicable to this equipment is growing. Although there has been active research on LCDs (liquid crystal displays), PDPs (plasma display panels), FEDs (field emission displays), OLEDS (organic light emitting diodes), etc as these flat panel display devices, liquid crystal displays (LCDs) highlighted due to such reasons as mass-production technology, easiness of driving means, high resolution, and large-sized screen.
A liquid crystal display displays an image by controlling light transmittance through an electric field applied to a liquid crystal capacitor in response to an input data signal. The liquid crystal display includes a liquid crystal panel for displaying an image, drive circuits for driving the liquid crystal panel, and a backlight unit for illuminating the liquid crystal panel.
Particularly, the liquid crystal panel displays an image as the light transmittance of a plurality of pixels is controlled by drive circuits connected to the liquid crystal panel. In general, the drive circuits of the liquid crystal display include a gate driver that allows a thin film transistor to conduct electricity by applying a gate drive signal to a gate line formed on the liquid crystal panel, a data driver that charges pixels by applying an analog waveform data signal to one electrode of the electrically conducting thin film transistor, and a timing controller that controls the two drivers.
FIG. 1 is a view schematically showing a data driver, one of the drive circuits of a conventional liquid crystal display device.
Among these drive circuits, the data driver consists of a plurality of data drive ICs. A data drive IC includes a shift register 2, a latch block 4, a DAC (digital analog converter) 6, and an output buffer 8, and converts input digital waveform image data into an analog waveform data signal in response to a data control signal output from the timing controller, outputs the analog waveform data signal to the liquid crystal panel, and allows the liquid crystal panel to display an image in response to this signal.
However, the liquid crystal display device is not capable of display images and colors while it is running in standby mode when all power is cut off, except when an input signal is received by remote control the viewer, rather than running in normal mode in which normal images are displayed. Hence, the viewer sees only black. As a result, the wall with the liquid crystal display device mounted on it is vastly covered in black, especially if it is large-sized, which does not blend in well with its surroundings and is not desirable from an aesthetic point of view.
Accordingly, there has been proposed a method of displaying a predetermined image in a repeating fashion for a long period of time, like in an electronic picture frame. However, this method is of no practical benefit for power saving since the power consumption of liquid crystal displays is increasing with the trend toward large-area liquid crystal displays and running an electronic picture frame therefore consumes the same amount of power as running a liquid crystal display in normal mode.
To overcome this limitation, there has been proposed a method of minimizing power consumption and improving interior functionality by displaying, during standby mode, a single color screen or a striped screen where a predetermined number of stripes shift on a regular basis, rather than displaying normal images.
However, even the single color screen or stripe screen consumes a larger amount of power than keeping the screen in black. Especially, the power consumption of analog circuits, i.e., the latch block 4, DAC 6, and output buffer 8, which constitute the data driver is 70% of the total power consumption of the liquid crystal display during standby mode, and therefore there is a need for a method to further lower the power consumption of the data driver.